Federal Republic of Germany Patent 19 46 052 describes and illustrates a measuring instrument of this type which is intended for use in the working of the wood surfaces or the like, in order for instance to adjust the mechanical working tools. For this purpose, the measurement instrument has two support feet the bottoms of which form the contact plane. In the center between the two support feet there is located the sensor pin which is displaceable axially against spring action. The sensor pin here actuates the indicating instrument which is connected via gearing to the sensor pin.
This known measuring instrument can only be used if the two support feet can come to rest on one and the same plane. In many cases of use however, this is not possible, for instance in the case of wood-milling cutters in which, in general, a stop having a fixed stop half and an adjustable stop half is provided. In actual practice, the operator, upon adjusting the milling tool, must then have recourse to test millings, which is disadvantageous not only because it means a loss of time and material but also because there is the danger of injuries since, in order to save time, the operator will not apply guard devices or covers during the test millings.